Waste removal system

ABSTRACT

A waste removal system that includes a toilet pan ( 28 ) for a ultra-low flushing volume toilet ( 20 ). The pan ( 28 ) includes a rearward end ( 28   a ) adapted for positioning substantially adjacent a cistern ( 22 ) and a frontward end ( 28   b ) adapted for positioning substantially remote the cistern ( 22 ). The pan ( 28 ) also includes a flushing water outlet having a primary outlet nozzle arrangement ( 42 ) disposed substantially adjacent the pan frontward end ( 28   b ) and adapted to direct flushing water ( 62 ) downwards and towards the pan rearward end ( 28   a ). The system also includes a related flushing method and drainline ( 90 ).

FIELD OF THE INVENTION

The present invention relates generally to a waste removal system andmore particularly to a ultra-low flushing volume toilet and a relatedtoilet pan, flushing method and drainline.

The expression “ultra-low flushing volume” is herein defined as havingnominal full and reduced flush volumes of about 3 liters and 2 litersrespectively.

BACKGROUND OF THE INVENTION

The design of water closets (WCs) in Australia has been greatlyinfluenced by the need to minimise water consumption and maintain anadequate sanitation system to safe guard and maintain a high level ofpublic health.

Since 1982 reductions in Australian WC flushing volume have lead to amajor lowering of the average daily WC water consumption per person from55 liters to 18 liters. A major contribution to this reduction was thedevelopment of the two button, dual flush WC having 6/3 liter reducedflush technology which gave the user the choice of applying either a 6liter full flush or a 3 liter reduced flush option to operate the WC.

OBJECT OF THE INVENTION

It is an object of the present invention to provide a toilet and relatedcomponentary that can operate directly into a sewer with a ultra-lowflushing volume.

SUMMARY OF THE INVENTION

Accordingly, in a first aspect, the present invention provides a toiletpan for a ultra-low flushing volume toilet, the pan including:

a rearward end adapted for positioning substantially adjacent a cistern;

a frontward end adapted for positioning substantially remote thecistern; and

a flushing water outlet having a primary outlet nozzle arrangementdisposed substantially adjacent the pan frontward end and adapted todirect flushing water downwards and towards the pan rearward end.

The pan preferably also has a S-bend outlet trap with a pan end andsewer end and the primary outlet nozzle arrangement is also adapted todirect flushing water towards and/or into the S-bend pan end.

The S-bend pan end includes a substantially straight pipe section andthe primary outlet nozzle arrangement is also adapted to direct flushingwater substantially parallel to the longitudinal axis of the pipesection.

A majority of the flushing water is preferably directed to the primaryoutlet nozzle arrangement.

The primary outlet nozzle arrangement preferably includes a plurality ofoutlet nozzles.

The pan preferably also has a secondary outlet nozzle arrangement, mostpreferably in the form of a single nozzle, disposed substantiallyadjacent the pan rearward end and adapted to direct a minority of theflushing water substantially downwards.

The pan preferably also has tertiary outlet nozzle arrangements, mostpreferably in the form of holes, disposed along the sides of the pan andadapted to direct a minority of the flushing water substantiallydownwards.

The pan preferably includes a rear wall leading to the S-bend and thesecondary outlet nozzle arrangement is adapted to direct flushing waterdownwards along the rear wall.

The minority of the flushing water is preferably directed to thesecondary outlet nozzle arrangement.

The pan preferably includes a manifold adapted for fluid communicationwith a flushing outlet of the cistern and the primary or the primary andsecondary outlet nozzle arrangements. The manifold preferablysubstantially replicates the shape of upper rim of the pan.

In one form, the manifold is formed separately from the pan and ispreferably releasably engageable therewith. In another form, themanifold is formed integrally with the pan. In a further form, themanifold is formed integrally with the toilet seat.

In a second aspect, the present invention provides a method of flushinga toilet pan for a ultra-low flushing volume toilet, the pan having arearward end adapted for positioning substantially adjacent a cisternand a frontward end adapted for positioning substantially remote thecistern, the method comprising directing a majority of a cistern'sflushing water in a concentrated jet from the upper forward end of thepan towards the lower rearward end of the pan in a directionsubstantially aligned with the frontward-to-rearward centreline of thepan.

The method preferably also comprises directing a minority of a cistern'sflushing water from the upper rearward end of the pan along a rear wallof the pan end towards the lower rearward end of the pan.

The method preferably also comprises directing a minority of a cistern'sflushing water down the sides of the pan.

The method preferably also comprises inducing a partial syphon actioninto the waste outlet of the pan by directing the majority of acistern's flushing water directly into the pan outlet in a directionsubstantially parallel to the longitudinal axis of the leading sectionof the pan outlet, whereby the partial syphon action lowers the level ofthe water in the pan during the commencement of the flush.

In a third aspect, the present invention provides a toilet pan for aultra-low flushing volume toilet, the pan comprising:

a flushing outlet; and

an outlet trap in fluid communication with the flushing outlet, theoutlet trap comprising a first downwardly concave lower bend and asecond upwardly convex upper bend,

wherein the pan cross-sectional shape at an upper level horizontallyaligned with the upper surface of the first bend defines a firstrelatively larger cross-sectional area and the pan's cross-sectionalshape at a lower level horizontally aligned with the lower surface ofthe second bend defines a second relatively substantially smallercross-sectional area.

Preferably, the first cross-sectional area is approximately double thesize of the second cross-sectional area.

The pan preferably has a substantially vertical rear wall section with alower edge substantially adjacent the first cross-sectional area. Therear wall is preferably upwardly angled from the rear of the pan atabout 0 to 10 degrees from horizontal.

The pan preferably has a front wall section between the first and secondcross-sectional areas, the front wall section having an upper relativelysteeply angled portion, a lower portion substantially parallel to anddisplaced rearwardly from the upper portion and an intermediaterelatively shallowly angled portion therebetween.

The geometric centre of the first cross-sectional area is preferablysubstantially horizontally aligned with a user's solid drop position.The second cross-sectional area is preferably wholly rearward of thesolid drop position.

In a fourth aspect, the present invention provides a drainline for aultra-low flushing volume toilet, the drainline characterised by aheight-to-width ratio between about 1.4:1 to 1.5:1 and an upperradius-to-lower radius ratio of about 3:1.

The drainline in preferably produced from extruded plastics material.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described, by way ofexamples only, with reference to the accompanying drawings in which:

FIG. 1 is a cross sectional side view of a first embodiment of a toiletsuite incorporating aspects of the invention;

FIG. 2 is a front view of the suite shown in FIG. 1;

FIG. 3 is a perspective view of the suite shown in FIG. 1;

FIG. 4 is a cross sectional side view of a second embodiment of a toiletsuite incorporating aspects of the invention;

FIG. 5 is a front view of the suit shown in FIG. 4;

FIG. 6 is a perspective view of the suit shown in FIG. 4;

FIGS. 7 to 17 are perspective views of examples of outlet nozzlearrangements; and

FIG. 18 is an end view of an embodiment of a drainline incorporating anaspect of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring firstly to FIGS. 1 to 3, there is shown a first embodiment ofa toilet suite 20 incorporating aspects of the invention. The suite 20generally comprises a full and reduced flushing volume cistern 22 (knownas a flush tank in the United States) operated by a pair of buttonactuators 24, which are accessible through the top surface of a cisternbody 26. The cistern 22 is placed within the larger cistern body 26 as,due to its ultra-low flushing volume, it would appear out of scale (ie.too small) with the remainder of the toilet suite 20.

The suite 20 also comprises a pan 28 connected to the cistern 22 by aflush pipe 30. A toilet seat 32 and lid 34 are pivotally mounted to thepan 28 by hinges, which are well known. The pan 28 has a rearward end 28a and a frontward end 28 b and a rim 36 about an opening 38.

A flushing water manifold 40 is located beneath the rim 36 and is influid communication with the flush pipe 30. The manifold 40 has aprimary outlet nozzle arrangement 42 positioned near the frontward end28 b of the cistern 28 and a smaller secondary outlet nozzlearrangement, in the form of single nozzle 44, positioned adjacent therearward end of the pan 28 a. The primary outlet nozzle arrangement 42has four outlet nozzles 46, which are best seen in FIG. 7. The manifold40 also has a number of tertiary outlet nozzle arrangements, in the formof holes 48, disposed along the sides of the pan 28.

In the preferred embodiment shown, the manifold 40 is a separate,substantially oval shaped plastic component that substantiallyreplicates the shape of the pan rim 36. In other embodiments (notshown), the manifold is formed integrally with the pan or with thetoilet seat.

The pan 28 also includes a flushing outlet 50 which is connected to amains sewerage system in a known manner. The flushing outlet 50 ispreceded by an S-bend outlet trap 51 formed from a first downwardlyconvex lower bend 52 and a second upwardly convex upper bend 54. The pan28 also has a rear wall 56 which is upwardly angled from the rear of thepan 28 at about 10° from horizontal. The front wall 58 of the pan 28 hasan upper relatively steeply angled portion 58 a, lower relativelysteeply angled portion 58 b, which is substantially parallel to andrearwardly displaced from the upper portion 58 a, and an intermediaterelatively shallowly angled portion 58 c therebetween. The portion ofthe pan 28 adjacent the lower front wall portion 58 b is substantiallycylindrical and has a central longitudinal axis 60.

The operation of the suite 20 will now be described. Pressing one of theactuator buttons 24 initiates flushing of the suite 20. The flushingwater is communicated from the cistern 22 to the flush pipe 30 and so tothe flushing water manifold 40. The majority of the flushing water(approximately 80%) exits the manifold 40 via the four nozzles 46 in theprimary outlet arrangement 42, as indicated by the large arrow 62 and isdirected towards the commencement of the S-bend outlet trap 51 in adirection substantially parallel with the axis 60 of the cylindricalportion of the pan 28 adjacent the front wall lower portion 58 b.Directing the flushing water 62 in this way concentrates the energy ofthe flushing water into the outlet trap 51 and results in adequateclearing of waste (equal to or better than current standards for known6/3 liter full/reduced flush toilet suites) within the pan 28 with the3/2 liter ultra-low flushing volumes. A minority of the flushing wateris directed through the outlet 44, as indicated by medium arrow 64, towet and clean the rear wall 56 of the pan. An even smaller amount of theflushing water is directed out of the holes 48 as indicated by smallarrows 66 to wet and clean the sides of the pan 28.

The water level in the pan 28 in the absence of a flush is denoted 68 inFIG. 1. During the previously described flushing action, the energy ofthe majority of the flushing water 62 creates a partial syphoning actionwithin the outlet trap 51 which results in the water level during theflush falling to approximately that denoted 70. The surface area at thelevel 70 is approximately half that at the level 68 and thecorresponding reduction in cross sectional area of the outlet trap 51further increases the velocity, and thus concentrates the energy, of theflushing water through the trap 51, further aiding in waste clearance.The larger surface area at the water level 68 also advantageouslyprovides a larger target area for user's wastes, particularly solidwastes. Further advantageously, the geometric centre of the surface areaof the water at level 68 is substantially vertically aligned with theapproximate solid waste drop position of a user.

Accordingly, before flushing, the pan 28 advantageously provides a largetarget surface area (at level 68) to minimise the likelihood of wastebeing incident on non wetted regions of the pan 28. During flushing, thepan 28 advantageously provides a reduced surface area (at level 70) toconcentrate the energy of the flushing water. This combination alsocontributes to the improved clearing of waste in the pan 28 withultra-low flushing volumes.

FIGS. 4 to 6 show a second embodiment of suite 80 incorporating aspectsof the invention which is similar to the suite 20 described withreference to FIGS. 1 to 3 and in which like reference numerals are usedto indicate like features. The difference between the suite 80 and 20 isthe suite 80 has a hand washing basin 82 integrally formed with thecistern body 26. After flushing, the mains water used to fill thecistern 22 is directed to a free outlet tap 84 whereafter it flows fromthe basin 82 through a pipe 84 and into the cistern 22. This arrangementprovides further reductions in overall water usage by allowing a user towash their hands with water that is then reused as flushing water ratherthan washing their hands in water that is directly returned to thesewer.

FIG. 7 is an enlarged detailed view of the preferred form of primaryoutlet nozzle arrangement 42. FIGS. 8 through 17 are similar views ofother primary outlet nozzle arrangements 42 with outlet nozzles 46.

The primary outlet nozzle arrangement 42 shown in FIG. 17 is the mostpreferred and is formed from upper and lower moulded halves 42 a and 42b respectively. The outlets 46 each receive a separate portion of theflushing water from either side of the manifold 40. This reduces theturbulence, and energy loss, of the two streams of water hitting eachother during entry to the primary outlet nozzle arrangement 42, comparedto earlier embodiments shown in FIGS. 7 to 15. Further, the outlets 46include upper, lower and side edges 46 a, 46 b and 46 e respectivelywhich are shaped to form the flow of flushing water (as exemplified bythe arrow 62 in FIG. 1) into a cross sectional shape similar to that ofthe surface of the water in the pan 28 at level 68. Directing andshaping the flushing water 62 to cover all of the water surface at level68 serves to maximise the amount of waste that is directed into thewaste S-bend outlet trap 51 and out through the flushing outlet 50.Concentrating and directing the energy of the flushing water 62 into thetrap 51 in this way improves waste clearance.

FIG. 18 is an end view of a drainline 90 suitable for use with theultra-low flushing volume toilet suites described above. The drainline90 is characterised by an internal height H to width W ratio betweenabout 1.4:1 and 1.5:1 and an internal upper radius R to lower radius rratio of about 3:1. It has been found that these ratios provide adrainline with an optimum balance between waste transportation at lowflow rates (less than 2.5 liters/second) due to increased flow velocityin the lower (and slimmer) portion of the drainline 90 and totalcapacity at high flow rates. The preferred size of the drainline 90 isan internal height H of 130 mm, internal width W of 90 mm, upperinternal radius R of 45 mm and lower internal radius r of 15 mm.

When the suites 20 and 80 were matched with the drainline 90, and theirperformance benchmarked against an industry leading 6/3 liter dual flushtoilet suite, the following results were obtained from a comparison ofpotable water usage and savings for the suites 20, 80 and the 6/3 literdual flush WC based on daily water usage per person of five flush cycles(one full flush and four reduced flush cycles).

Daily water Average flush Percentage WC system usage per person volumesaving 6/3 liter dual flush   18 liters  3.6 liters — (benchmark) Suite20   11 liters  2.2 liters 39% Suite 80 9.38 liters 1.88 liters 48%

Although the invention has been described with reference to preferredembodiments, it will be appreciated by those skilled in the art that theinvention is not restricted to such preferred embodiments. For example,the invention is also suitable for use with pans that have a P-bendoutlet trap.

1. A toilet pan for an ultra-low flushing volume toilet, the pancomprising: a flushing outlet; an outlet trap in fluid communicationwith the flushing outlet, the outlet trap comprising a first downwardlyconvex lower bend and a second upwardly convex upper bend; a front panwall comprising: a front upper portion being relatively steeply angled;a front lower portion substantially parallel to and displaced rearwardlyfrom the upper portion; and an intermediate portion arranged between theupper and lower portions and being relatively shallowly angled; and arear pan wall comprising: a rear upper portion; and a rear lower portionhaving an upper end and a lower end, the upper end located at anintersection between the rear lower portion and the rear upper portion,the rear lower portion being substantially parallel to the front lowerportion, wherein the front lower portion and the rear lower portiontogether define a passage of substantially constant cross-sectional areaextending from the upper end of the rear lower portion to the lower endof the rear lower portion, and wherein a first cross-sectional area ofthe pan at an upper level horizontally aligned with the upper end of therear lower portion is larger than a second cross-sectional area of thepan at a lower level horizontally aligned with the lower end of the rearlower portion, the intermediate portion being arranged between the firstand second cross-sectional areas.
 2. The pan as claimed in claim 1,wherein the first cross-sectional area is approximately double the sizeof the second cross-sectional area.
 3. The pan as claimed in claim 1,wherein the pan has a substantially vertical rear wall section with alower edge substantially adjacent the first cross-sectional area.
 4. Thepan as claimed in claim 3, wherein the rear wall is upwardly angled fromthe rear of the pan at about 0 to 10 degrees from horizontal.
 5. The panas claimed in claim 1, wherein the geometric centre of the firstcross-sectional area is substantially horizontally aligned with a user'ssolid drop position.
 6. The pan as claimed in claim 1, wherein thesecond cross-sectional area is rearward of the solid drop position.